1. Field of the Invention
The present invention relates to a heat dissipation device, and more particularly to a heat dissipation device which has a plurality of heat pipes surrounding a heat sink to form a closed circulation route.
2. Description of Prior Art
During operation of many heat generating devices such as central processing units (CPUs), large amounts of heat are produced. Such heat must be quickly removed from the heat generating device, to prevent it from becoming unstable or being damaged. Typically, a heat dissipation device is attached to an outer surface of a heat generating device to remove heat therefrom.
Referring to FIG. 14, a conventional heat dissipation device comprises a hollow chassis, working liquid received in the chassis, and a plurality of fins extending upwardly from the chassis. In operation, the chassis conductively absorbs heat from a heat generating device. The working liquid absorbs such heat, and then transfers the heat to the fins by phase transition, convection and circulation. However, convection of the working liquid within the chassis is often poor. As a result, the heat dissipation device cannot adequately dissipate heat from the heat generating device.
Referring to FIG. 15, another conventional heat dissipation device 20 comprises a metal block 26, a heat pipe 21 and a plurality of parallel fins 22. The metal block 26 is directly mounted on an outer surface of a heat generating device (not shown). One end of the heat pipe 21 is engaged in an aperture 23 of the metal block 26, and an opposite end of the heat pipe 21 is extended through apertures 24 of the fins 22 to be in intimate thermal contact with the fins 22. However, the thermal contact surface of the both ends of the heat pipe is limited. Accordingly, the heat removal capability of the heat dissipation device is frequently not sufficient.
Thus, an improved heat dissipation device which overcomes the above-mentioned problems is strongly desired.
Accordingly, an object of the present invention is to provide a heat dissipation device which has a plurality of heat pipes surrounding a heat sink to attain great heat removal capability.
Another object of the present invention is to provide a heat dissipation device having simple and compact structure.
In order to achieve the objects set out above, a heat dissipation device in accordance with a preferred embodiment of the present invention comprises a heat sink, a plurality of first pipes, a pair of second pipes and working liquid. The heat sink comprises a base, and a plurality of fins attached on the base. A plurality of parallel first holes is defined through the base. A second hole is defined through a middle of the base in a longitudinal direction that is perpendicular to the first holes. The first and second pipes and the first and second holes thus cooperatively form a closed circulatory route. The working liquid is received in the circulatory route. In operation, the base absorbs heat from a heat generating electronic device. The working liquid absorbs some of that heat, and circulates through the circulatory route. Thus the first and second pipes dissipate said heat to airspace beyond the fins of the heat sink. Accordingly, the first and second pipes increase a heat dissipation area of the heat dissipation device. The heat removing capability of the heat dissipation device is optimized.
Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: